Synthesis And Study Of Triphenylamine-Cyano Fluorescent Molecules

Triphenylamine and its derivatives are provided with hyperconjugation effect and adept at hole mobility, which have been widely used in the field of electric-charge transport material, electroluminescent material, molecular probes etc. Triphenylamine centers on nitrogen atom, with three benzene rings placed in a three-propeller type inside. Since the three benzene rings are active chemically, modification can be easily made on them. Many optical materials which have special functions can be obtained by connecting different genes with the three outside benzene rings. Cyano (-CN) as a strong electron-withdrawing group, can promote the process of intramolecular charge transferring and make dipole of the molecule. Introducing one or more cyano in design and synthesis of functional materials can improve the performance of these materials to a certain extent. In this paper, The para position of the three benzene rings of triphenylamine by the Vilsmeier-Haack reaction synthesize into derivative which contain one, two, or three aldehyde. Based on above-mentioned derivative, a series of triphenylamine fluorescent molecules with special properties have been synthesized, and further study on the structural&photoelectric properties of these molecules shall be undertaken. The main contents of this thesis are as follows:1、Five categories of TPA-Malononitrile derivatives with D-A structure are synthesized by Knoevenagel condensation reaction. Tests show that compounds1-5appear a certain crystallization property, but crystallization properties gradually weaken with the increase of the branches through XRD, SEM and TGA. All of them are present excellent thermal stability, and it can improve about30℃with the introduction of-Br, which can expand their range of applications. Using UV-vis, FL and other measures to test their optical performance, the results show that the absorption and the lengths of emission wave are red-shifting gradually, provided that the numbers of cyano for compound1-5are increasing. The maximum absorption wavelength of compounds1-5 in dichloromethane solution is in the range of440nm-475nm and maximum emission wavelength at536nm-578nm with strong yellow or green fluorescence. After the polarity of the solvent was changed, compounds1-5showed an excellent solvatochromism property; when increasing solvent polarity, FL and Stokes shift were greatly affected by it. Wherein the maximum emission peak of the FL occurs more than40nm red shift, exhibit good solvent relaxation phenomena.2、Compounds M1and M2are synthesized by the Witting reaction with phenyl as a core and triphenylamine as the electron donating group and-CN as the electron-withdrawing group. Tests show that compounds Ml, M2appears a certain crystallization property through XRD, SEM and TGA, and M1is a needle crystal compound, the crystallinity of compound M2is significantly decreased, which is required for OLED materials. All of them are present excellent thermal stability and has a relatively high decomposition temperature (Td)(respectively390℃and140℃), meeting the requirements of OLED materials. Using UV-vis, FL and CV to test their optical performance, the results show that the maximum absorption wavelength of compound M2in dichloromethane solution increased to466nm, maximum emission wavelength increased to560nm with strong yellow fluorescence. The results show that cyano has obvious adjustment. After the polarity of the solvent was changed, the UV-vis absorption, FL emission of compounds M1、M2appear obvious red shift of30nm or more. In summary, the compounds M1, M2owns excellent thermodynamics and optical properties, particularly M2may have potential application as a material for OLED, etc.